A low power variable optic (LPVO) is a rifle scope with a variable magnification range that starts at 1x, 2x, or 3x. Unlike fixed-power optics, LPVOs let you dial between close-quarters and extended-range shooting without swapping optics. EDC Index includes optics with a minimum magnification of 1x, 2x, or 3x. Optics starting at 4x or higher are a different category and are not included here.
This is the most important spec to understand before buying an LPVO.
In a first focal plane (FFP) optic, the reticle scales with magnification. At 2x, the reticle appears half the size it does at 4x. The result is that reticle subtensions — the hash marks used for holdovers and ranging — are accurate at every magnification setting. If your reticle says a mark is 1 Mil, it is 1 Mil whether you are at 2x or 8x.
In a second focal plane (SFP) optic, the reticle stays the same apparent size regardless of magnification. Subtensions are only accurate at one specific magnification, usually maximum. At any other power, the marks are off by a proportional amount.
For a shooter who uses the reticle only as an aiming point and never references subtensions, SFP is fine. For anyone using holds, ranging, or drop compensation at varied magnification settings, FFP is the correct choice.
Reticle subtensions and turret adjustments are measured in one of two units: MOA (minute of angle) or Mil (milliradian).
One MOA is approximately 1.047 inches at 100 yards, typically rounded to 1 inch for practical use. One Mil is 3.6 inches at 100 yards.
Neither is more accurate than the other. The difference is the math involved in fieldwork. Mil uses a base-10 system that makes mental arithmetic faster for most shooters. MOA produces smaller increments, which some shooters prefer for fine adjustments at long range.
The more important rule: your reticle unit and your turret adjustment unit should match. A Mil reticle paired with MOA turrets requires unit conversion every time you dial a correction. EDC Index lists both Reticle Unit and Adjustment Unit as separate fields so you can filter for matching systems.
LPVO tubes come in three standard diameters: 30mm, 34mm, and 35mm. Tube diameter affects two things: mount compatibility and internal adjustment range.
Larger tubes provide more internal adjustment travel, which matters for extreme long range or when mounting on a rifle with significant cant. For most LPVO use cases in the 1-10x range, 30mm provides adequate adjustment range.
The practical impact for most buyers is mount selection. Rings and mounts are sized to tube diameter. A 34mm optic requires 34mm rings. Verify your mount before purchasing.
The minimum magnification matters more than the maximum for most LPVO applications.
A true 1x setting allows both-eyes-open shooting and functions like a red dot at close range. This is critical for carbine competition, home defense, and any scenario requiring fast target acquisition at short distances. Not all 1x optics are equally usable at 1x — eye box, parallax behavior, and exit pupil all affect how true the 1x experience feels in practice.
Maximum magnification determines how useful the optic is at distance. A 1-6x is a capable general-purpose setup. A 1-8x or 1-10x extends effective ranging and precision holds but adds size, weight, and cost. More magnification is not always better — a 1-10x at max power has a narrower field of view and less forgiving eye box than a 1-6x at the same power level.
Choose minimum magnification based on your closest expected engagement distance. Choose maximum based on your farthest.
A ballistic drop compensation (BDC) reticle includes aiming points calibrated for bullet drop at specific distances, typically marked in yards or meters rather than angular units. Instead of calculating a holdover, you select the mark that corresponds to your target distance.
The tradeoff is specificity. A BDC reticle is calibrated for a particular cartridge, bullet weight, and muzzle velocity. If your load does not match the calibration, the marks will be wrong by a proportional amount. Switching ammunition can make a BDC reticle unreliable without recalibration.
A standard MOA or Mil reticle requires the shooter to calculate or reference a drop chart, but works correctly with any load once the dope is established.
EDC Index lists BDC as a Yes/No field so you can filter for reticles with or without ballistic drop compensation independently of the underlying subtension system.